Sets a flag to indicate that when the preconditioner needs to apply (part of) the operator during the preconditioning process it applies the Amat provided to TSSetRHSJacobian(), TSSetIJacobian(), SNESSetJacobian(), KSPSetOperator() or PCSetOperator() not the Pmat.
-pc_use_amat <true,false> -
Notes:
For the common case in which the linear system matrix and the matrix used to construct the
preconditioner are identical, this routine is does nothing.